Child resistant packages for medicine and poison containers have been devised in the prior art for the protection of young children. Among the prior art types of safety closures are those which involve the ratcheting engagement of teeth on a container screw cap with a yielding locking element or tooth on the container neck or body portion, the container locking tooth responding to a downward manual pressure to effect release of the closure of the child resistant package. Examples of such prior art type of cap are contained in U.S. Pat. Nos. 3,700,133; 3,884,379; 3,892,326 and 3,902,620. Other types of packages have radially deflectable lugs as shown in U.S. Pat. Nos. 4,427,124; 4,984,002 and 5,413,233.
It is also known in the prior art to provide a child resistant package in which a movable release element on the closure responds to lateral or side pressure to free the cap from interlocking engagement with teeth or other like projection means on the container. In U.S. Pat. No. 4,036,385, the child resistant package consists of a container body having a yielding resilient manually operable release element positioned on the side wall of the container near the end thereof which receives a screw-threaded closure. The release element carries a single upstanding locking lug which is capable of ratcheting to interlocking engagement with a locking lug on a bottom skirt member of the threaded cap during rotation of the closure to gradually tighten it down on the threaded portion of the container. The release element responds to pressure applied by the thumb at one side of the container to shift the lug of the release element inwardly on a substantially radial path relative to the axis of the container and container closure. This movement separates the lug on the release element from the locking lug of the threaded closure so that the closure may be removed by simple rotation. The arrangement presents a complex manipulation necessary to effect release of the cap which achieves the result of making it difficult for small children to operate.
United States patent application Ser. No. 08/608,877 filed Feb. 29, 1996, now U.S. Pat. No. 5,711,442, discloses a child resistant package including a container having an open end and multiple threads on an external surface of the container adjacent the upper end. A closure having a base wall and a peripheral skirt has an inner surface formed with multiple threads corresponding in number to the multiple threads on the container for engaging the threads on the container. A release element is formed integrally on the exterior surface of the container below the threads. The release element includes an integral axial lug extending upwardly toward the open end of the container. The closure has a plurality of circumferentially spaced stops on the inner surface of the skirt of the closure below the threads corresponding in number to the threads on the closure and the number of threads on the container. The lug on the release element normally extends upwardly for engagement with at least one of the stop lugs such that when the release element is pressed radially inwardly, the lug is disengaged from engagement with a stop and the closure can be removed by unthreading the closure from the container.
Among the objectives of the present invention are to provide a child resistant package which is consumer friendly; wherein the child resistant package is easy to apply and close; wherein the child resistant package requires a lesser force or torque when the closure is rotated to apply the closure to the container that is substantially less than the torque required to remove the closure from the container; wherein the child resistant package minimizes the wear on a locking lug during application of the closure to the container; wherein the child resistant package minimizes the deflection of the release element on the container when the closure is rotated to apply the closure to the container; wherein the child resistant package has a locking lug which provides sufficient rigidity to resist removal of the closure without deflecting when a torque is applied in an attempt to remove the closure from the container without manipulating the release element; wherein the child resistant package includes provision for controlling the deflection of the release element on the container; and wherein the child resistant package makes it more likely that an older adult will fully apply the closure.
In accordance with the invention, a child resistant package includes a container having an open end with a single thread or multiple threads on the external surface of the container adjacent the upper end. A closure having a base wall and a peripheral skirt has an inner surface formed with single or multiple threads corresponding in number to the multiple threads on the container for engaging the threads on the container. A deflectable release element is formed integrally on the exterior surface of the container below the threads. The release element includes an integral axially deflectable lug extending upwardly toward the open end of the container. The closure has at least one locking lug on the inner surface of the skirt of the closure below the threads, the number of locking lugs preferably corresponding in number to the number of threads on the closure and container. The deflectable lug on the release element normally extends upwardly for engagement with a stop such that when the deflectable release element is pressed radially inwardly, the deflectable lug is disengaged from engagement with a locking lug and the closure can be removed by unthreading the closure from the closure. When the closure is reapplied minimal torque is required due to the axial deflection of the lug and the locking lug on the closure moves past the deflectable lug.
In a preferred form of the child resistant package, the deflectable release element includes means thereon which when deflected engages means on said container to limit the deflection on the deflectable release element in an axial direction. Such interengaging means comprises a pair of axial projections on the deflectable release element and a pair of stops on the container which are brought into engagement upon excessive deflection of the release element.